The LH/CG (luteinizing hormone/chorionic gonadotropin) Receptor present on the cell surface of granulosa/luteal cells and Leydig cells is of critical importance in the regulation of gonadal function. One of the long-range goals of our laboratory is to delineate the steps in the synthesis (including transcriptional, translational, and processing events) and the degradation of the LH/CG Receptor and to identify those points under hormonal regulation. Specifically, the following is proposed: (i) Elucidate the structure of the LH/CG Receptor in both murine Leydig tumor cells and in rat granulosa cells using different methodological approaches, and determine if hCG occupancy of the Receptor causes Receptor phophorylation; (ii) Prepare monoclonal antibodies to the LH/CG Receptor; and (iii) Determine (directly) the rates of synthesis and degradation of the LH/CG Receptor and how these rates are affected by agents which are known to modulate levels of the Receptor. These studies will allow us a much better understanding of how the hormones LH and CG interact with their cell surface receptor, how this is translated into a cellular response, and how other hormones and agents modulate this response. Furthermore, they will provide the groundwork for future experimentation exploring the regulation of the LH/CG Receptor in progressively more detail. The results of these studies are important not only in the context of gonadal function, but also in the context of our understanding the general underlying mechanisms whereby a variety of hormones affect cell function by interacting with cell surface receptors.